METHOD OF DETERMINING DEFORMATION IN A STRUCTURE

摘要

A method of determining deformation in a structure around which a sensing optical fiber is helically wound, includes performing a distributed measurement at a point along the fiber, to obtain a frequency gain spectrum at that point. Performing a distributed measurement includes, adjusting a pulse width of a pulse pump signal to achieve a predefined spatial resolution and providing the pulse pump signal with adjusted pulse width in the fiber to generate scattering, which is used to obtain the frequency gain spectrum. Identifying at least two curves which, when added together, best fit the frequency gain spectrum. Identifying the frequency at which peaks of the curves occur. Determining deformation in the structure by determining deformation in the fiber at the point using a frequency at which a peak of an identified curve occurs. The amount of deformation in the fiber corresponds to the amount of deformation in the structure.

主权项

1. A method of determining deformation in a structure around which at least one sensing optical fiber is helically wound, the method comprising the steps of:
(a) performing a distributed measurement at a point along the at least one sensing optical fiber, to obtain a frequency gain spectrum at that point, wherein the step of performing a distributed measurement comprises, adjusting a pulse width of a pulse pump signal so as to achieve a predefined spatial resolution for the detection of deformation, and providing the pulse pump signal with adjusted pulse width in the sensing optical fiber to generate scattering which is used to obtain said frequency gain spectrum, wherein said predefined spatial resolution for the detection of deformation is a value which is within the range ‘(pitch of the helical wound sensing optical fiber)−(50% of the pitch of the helical wound sensing optical fiber)’-‘(pitch of the helical wound sensing optical fiber)+(50% of the pitch of the helical wound sensing optical fiber)’; (b) identifying at least two curves which, when added together, best fit the frequency gain spectrum; (c) identifying the frequency at which peaks of the at least two curves occur; (d) determining deformation in the structure by determining deformation in the at least one sensing optical fiber, at said point at which the distributed measurement was performed, using a frequency at which a peak of an identified curve occurs, wherein the amount of deformation in the sensing optical fiber corresponds to the amount of deformation in the structure.